Again, that can very easily be reflected in population numbers in each settlement. I mean, the tax and levy numbers need to come from something right? I doubt each settlement gives some fixed amount. So Stockholm would naturally give you more tax income and manpower, than some brand new settlement in the northern frontiers. Hence my original argument that the number of settlements should rather be limited in areas where clear geographic difficulties make it impossible or very hard to maintain several settlements. An area with lots of mountains might not have practical room for more than a few towns, deep regions in Siberia might be too remote and cold to sustain a large number of settlements, deserts might be too inhospitable and lacking in basic needs such as water to sustain many settlements, and here I agree that the settlement cap could be lowered.Thing is, when we're dealing with sums of 8 for the most developed regions in Europe, like the north Italian city-states, even with a very kind way of measuring the population and development of Scandinavia/the nordic countries, those sums are rather correct. I am not arguing for a completly undevelopable north (because that would be both incorrect and boring) but the north had no way to reach the population of earlier mentioned Netherlands and Italy. There just couldn't be taht amount of babies.
But again, limiting settlements based on historic populations seems like a poor way to go about it, specially when its in the players power to change history. Northern Norway had a rather robust population comparable to many other regions in Norway at the time. Only in the 1600s-1700s did the population start to decline when market prices for fish dropped in Europe. That shows you that they prospered and grew due to trade... and declined due to lack of trade. Like so many other settlements around Europe.